Question

Set `X` = `{1, 2, 3, 4}` and Set `Y` = `{5, 6, 7, 8}`. How would we write the 'union', `nn`, and the 'intersection', `uu`, of `X` and `Y`?

Answer 1

`XuuY` is the 'union' of the sets `X` and `Y`: `XuuY=`{1,2,3,4,5,6,7,8}

`XnnY` is the 'intersection' of `X` and `Y` - the set of elements that are in both sets. In this case, since no elements are in both sets, `XnnY=`{ }